Drives for Web Handling

Many drives have provision to compensate for friction. This is important for center winders and unwinds, particularly if these are controlled with tension through torque. Friction may be static friction, rolling friction and losses due to windage inside the motor, around all rotating elements and air that follows the web.Friction for rotating machinery is measured as the torque needed to overcome it. Many aspects of friction can be measured in a very simple way. Without the web, run the equipment at various RPMs. I suggest measurements at 1% RPM, 2%, 5% 10%, 20%, 30% to 100%. The measurement is the drive torque required to run the equipment at that RPM. This friction measurement considers many factors contributing to friction, but not all of them. For instance, the windage friction associated with the web is not measured in this way.Apply friction compensation as determined by these measurements. This will require the help of a skilled drive technician. This will compensate for about 90% of friction effects.The next step in setting friction correctly requires running the line with the web. The tension regulator will overcome the remaining friction in the system. By looking at the output (CV) of the tension regulator, askilled drive technician can determine the remaining friction as a function of line speed and roll diameter. Expensive, time-consuming work, but tension improvements can be made.​

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Clarence Klassen

This Technical Topic Channel presents information of interest to electrical engineers, electrical maintenance and project managers involved with web handling. It is moderated by Clarence Klassen, and includes White Papers, questions from readers and comments on industry issues.